1. Field of the Invention
This invention relates, generally, to the medical arts. More particularly, it relates to means for sealing openings in a mammalian body created by any means.
2. Description of the Prior Art
Openings may be formed in a human or other mammalian body by numerous means. Needles or other medical instruments may create puncture or other types of openings, for example. Moreover, electrical, ultrasound, optical instruments and the like may create openings. Gunshot and knife wounds and numerous other events may also cause openings to be formed.
An opening in a lung is undesirable because air leaks therefrom and causes the lung to collapse. However, openings in soft tissue, as well as openings in internal organs, such as the heart, kidney, liver, etc., also require closure. Openings in bones, cartilage, ligaments, and other hard tissue must also be closed.
Many techniques have been developed for the surgical closing of openings. Sutures were invented long ago, for example. One important drawback to using sutures in some applications arises from the fact that the needle used to sew the suture in place typically has a diameter that is larger than the suture. Thus, if a suture is used to close an opening in a lung, for example, air can escape from the lung in the space that surrounds the suture, i.e., the space has the diameter of the needle and is not fully occupied by the suture. This problem is addressed by applying an adhesive over the suture; when the adhesive cures, the openings around the suture are sealed. However, adhesives are difficult to apply and control and require time to cure.
Another more recently developed technique for closing openings includes the use of staples. The force required to apply staples may result in torn tissue. One solution to this problem is to apply an adhesive over the staples to seal the torn areas, just as is done in connection with sutures.
Adhesive have been used to close other openings in the body as well. Laparoscopic and endoscopic procedures, for example, may require sophisticated instrumentation. In situ curing of adhesives may be problematic depending upon the application, and may require the use of curing agents and other means for cross-linking free radicals to form the required bond. The curing agent may be air, visible light, ultraviolet light, heat, laser beams, chemical compounds that require mixing with one another, and so forth.
It would be advantageous therefore, if means for closing an opening could be found that did not rely upon adhesives and curing agents.
Numerous medical procedures and even non-medical events can result in openings in the body that need to be sealed, as mentioned earlier. Openings must be closed not just to stop the escape of air from the lungs, but to also stop the escape of body fluids from other body parts. Sealing means for closing openings are needed to stop the flow of blood, cerebral spinal fluid, and other fluids.
For exemplary purposes, an opening made by a biopsy needle will be considered. In a biopsy procedure, a needle adapted to collect tissue is inserted into a suspected lesion, usually multiple times. When a sufficient quantity of the lesion has been collected, it is taken to a lab for analysis.
To perform the procedure, a coaxial needle is first inserted so that its leading end is positioned near the suspected lesion. A biopsy needle is then inserted through the coaxial needle.
The puncture opening made by the coaxial needle may close and heal naturally if the lesion is in soft tissue such as a breast. However, if a lesion is in the lung, the puncture opening made by the coaxial needle may need to be closed quickly. The use of sutures or adhesives, or sutures and adhesives, are well-known as already mentioned, but such techniques have limitations.
What is needed, then, is an apparatus for closing an opening in a lung or other vascular organ as well as in soft or hard tissue. The needed apparatus should close an opening quickly but should not cause problems of the type associated with adhesives.
Physicians often have a need to re-visit a surgical procedure site to monitor a patient""s recovery. However, the sutures and adhesives now in use include no means for helping a physician find the surgical site when a follow-up look is desired.
Thus there is also a need for a means that would enable a surgeon to locate a surgical site in the days, weeks, or months following a surgical procedure.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.
The long-standing but heretofore unfulfilled need for a method and apparatus for sealing openings made by medical or non-medical procedures in a mammalian body is now met by a new, useful, and nonobvious invention.
A first embodiment of the invention includes a plug formed of a preselected bioabsorbable material that expands in response to a predetermined stimulus. The plug is sized to fit within the opening prior to application of the predetermined stimulus to the dehydrated plug. The plug expands upon application of the predetermined stimulus thereto until the plug seals the opening. In this way, the plug, when expanded, prevents flow of liquid or gaseous fluid through the opening. The plug is gradually bioabsorbed as natural processes heal the opening. The preselected bioabsorbable material is a dehydrated hydrogel and the predetermined stimulus is moisture that is naturally present in the mammalian body.
The plug may have a solid, cylindrical configuration prior to application of the predetermined stimulus thereto so that the plug is adapted to fit into a lumen of a needle to facilitate introduction of the plug into the opening.
If the plug is to be employed as a scaffold for tissue regeneration, it may be provided in forms more suitable for that purpose. For example, it may have a corkscrew configuration at one end. It may also be designed to provide a mechanical anchor as well, having a leading end that expands radially outwardly after placement to prevent unintended outward migration of the plug.
The plug is impregnated with a contrasting agent to facilitate detection of the plug by imaging means selected from the group of imaging means consisting of magnetic resonance imaging, ultrasound, Doppler, and roentgenological means including x-ray, CT scan, mammography, and fluoroscopy.
Alternatively, the plug includes a radioactive substance detectable by a radiation detecting means including a gamma counter and a scintillation counter. In another alternative, the plug includes a transmitting means adapted to transmit signals in the electromagnetic spectrum that are detectable by receivers adapted to receive signals in the electromagnetic spectrum.
The plug is adapted to be slideably disposed in a lumen of a needle. A plug displacement means is adapted to abuttingly engage and slidingly displace the plug within the lumen to a preselected location near a distal end of the lumen. Withdrawal of the needle coupled with maintaining the plug displacement means at said preselected location during the withdrawal results in placement of the plug at the preselected location. Withdrawal of the plug displacement means does not cause displacement of the plug.
The novel material also has utility in promoting angiogenesis in a mammalian heart. A cavity or bore is formed in a heart and growth factor means is introduced into the bore. A bioabsorbable plug that expands in response to a predetermined stimulus then plugs the bore. The predetermined stimulus is applied to the bioabsorbable plug so that the bioabsorbable plug expands and seals the growth factor means within the bore.
The novel plug has further utility as a means for preventing loss of spinal fluid from the thecal sac. An opening is formed at a preselected site in the thecal sac by a biopsy needle introduced to the preselected site through a coaxial needle. The biopsy needle is withdrawn from the preselected site after the opening has been formed. A delivery catheter having a dehydrated, bioabsorbable plug formed of a preselected material that expands in response to a predetermined stimulus positioned in its lumen is then introduced through the coaxial needle to the preselected site. The dehydrated, bioabsorbable plug is pushed from the lumen of the catheter into the opening and said catheter is withdrawn from the preselected site. The bioabsorbable plug expands upon being hydrated by natural fluids present at the preselected site. The expansion holds the plug in place and further serves to prevent leakage of spinal fluid from the opening.
The novel material is not limited to plugs. For example, it may also be formed into a cylindrical member that slideably receives a plug. Such a cylindrical member and a plug may be used with one another to provide a means for sealing an incision in an artery. More particularly, a guide wire is inserted through the incision and a lumen of an introducer sheath is placed in receiving relation to the guide wire so that a leading end of the introducer sheath is guided to the incision by the guide wire. The leading end of the introducer sheath is positioned into abutting and surrounding relation to the incision. A dehydrated, bioabsorbable tube formed of a preselected material that expands in response to a predetermined stimulus is pushed from a lumen of the introducer sheath so that a leading end of the dehydrated, bioabsorbable tube is disposed in abutting and surrounding relation to the incision. The guide wire and the introducer sheath are then withdrawn from the artery. The leading end of a delivery catheter having an external diameter less than an internal diameter of the dehydrated, bioabsorbable tube is then introduced into the lumen of the dehydrated, bioabsorbable tube. A dehydrated, bioabsorbable plug formed of a preselected material that expands in response to a predetermined stimulus is positioned in a lumen of the delivery catheter and is pushed from said lumen into the lumen of the dehydrated, bioabsorbable tube. The delivery catheter is withdrawn and the dehydrated, bioabsorbable plug expands within the lumen of the dehydrated, bioabsorbable tube when contacted by natural moisture within the blood flowing through the artery. The dehydrated, bioabsorbable tube expands when contacted by the natural moisture within the blood and by natural moisture within tissue that surrounds the artery.
In another embodiment, an elongate suture is formed of a preselected bioabsorbable material that expands in response to a predetermined stimulus. The elongate suture is adapted to be pulled by a needle so that the elongate suture is used to sew closed the opening. The elongate suture has a diameter slightly less than a diameter of the needle, there being a clearance space about the elongate suture equal in diameter to the diameter of the needle less the diameter of the elongate suture. The elongate suture expands upon application of the predetermined stimulus thereto until the elongate suture seals the clearance space. The elongate suture, when expanded, prevents flow of liquid or gaseous fluid through the clearance space and is gradually bioabsorbed as the opening is healed by natural processes. The preselected bioabsorbable material is a hydrogel and the predetermined stimulus is moisture that is naturally present in a mammalian body. The elongate suture may be impregnated with a contrasting agent to facilitate its detection by imaging means selected from the group of imaging means consisting of magnetic resonance imaging, ultrasound, Doppler, and roentgenological means including x-ray, CT scan, mammography, and fluoroscopy. The elongate suture may include a radioactive substance detectable by a radiation detecting means including a gamma counter and a scintillation counter. Alternatively, it may include a transmitting means adapted to transmit signals in the electromagnetic spectrum that are detectable by receivers adapted to receive signals in the electromagnetic spectrum. Moreover, the elongate suture may be hollow and filled with a gaseous fluid.
A conventional suture, both bioabsorbable and nonbioabsorbable, may be coated with a material that expands in response to a predetermined stimulus and used in the same way as the suture made entirely of the novel material. This type of coating also provides a lubricious surface having a low coefficient of friction to minimize trauma during the suturing process.
A rigid medical staple of the type used in anastomosis of organs may also be coated with a preselected bioabsorbable material that expands in response to a predetermined stimulus to fill the openings made by the stapling procedure.
An important object of this invention is to provide a means for sealing openings in a mammalian body quickly and in the absence of conventional sutures, staples, and adhesives.
Another object is to provide a bioabsorbable means for sealing such openings.
Another major object is to provide a marking means that enables a physician to easily find a surgical site for follow-up purposes.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.